The present invention relates in general to a fifth wheel device for mounting on a vehicle for towing a wheeled container, and more specifically relates to a novel portable, self-contained fifth wheel device for manually detachable mounting on a vehicle, such as a fork lift truck or the like, for pulling a wheeled container, such as a trailer.
Such fifth wheel device has particular application, for example, in moving trailers of the tractor-trailer type from one location to another, such as in dock areas, freight terminals, and at other such locations where tractor-type trailer units are employed for the transportation of cargo.
Heretofore, trailers of the type employed with tractor-trailer units have been moved from location to location at the loading and/or unloading areas primarily either by large type cranes or by specially designed tractor units having a fifth wheel for engagement with the trailer chassis. It will be appreciated that such large type cranes are not only costly from an initial investment and maintenance standpoint, but also are not sufficiently efficient for quick and easy movement or "spotting" of the trailers since they are relatively slow moving and often, due to their size, cannot be used in areas where space is at a premium. In addition, such cranes require highly skilled operators and often cannot handle extremely heavy cargo loads held by the containers. Although fifth-wheel type tractors may be employed for moving and "spotting" the trailers, such vehicles are relatively expensive and again require the use of special operators.
A portable fifth wheel device is disclosed in U.S. Pat. No. 3,881,619 but this device requires a complex system for coupling the portable fifth wheel device to the vehicle, such as a fork lift truck. Accordingly, should such type of equipment break down, there results considerably increased cost by reason of the down-time encountered in order to repair such device resulting in costly delays in loading and/or unloading the cargo from ships, trains and the like. Moreover, due to the vital time schedules involved with the present day transportation facilities, it is imperative that the cargo be loaded and/or unloaded with the minimum time and effort within the given time schedule.